/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Public/GeometryCollection/GeometryCollectionISMPoolComponent.h
Preallocate an ISM in the pool. Doing this early for known mesh instance descriptions can reduce the component registration cost ofAddMeshToGroup()for newly discovered mesh descriptions.
void PreallocateMeshInstance ( const [FGeometryCollectionStaticMeshInstance](API\Runtime\GeometryCollectionEngine\GeometryCollection\FGeometryCollect-_22) & MeshInstance )